Heat exchangers



HEAT EXCHANGERS 2 Sheets-Sheet 1 Filed Aug. 1, 1957 FIGJ.

DRAIN PRESSURE INVENTOR. FRANK L. SCHWARTZ ATTO Dec. 20, 1960 Filed Aug. 1, 1957 F. L. SCHWARTZ 2,965,361.

HEAT EXGHANGERS 2 Sheets-Sheet 2 w J L 0 x in INVENTOR.

FRANK L. SCHWARTZ ATTO '7' EYS HEAT EXCHANGERS Frank L. Schwartz, Ann Arbor, Mich., assignor to Continental Aviation and Engineering Corporation, Detroit, Mich., a corporation of Virginia Filed Aug. 1, 1957, Ser. No. 675,698

2 Claims. (Cl. 257-267) compressor air to the exhaust cuts down on the efficiency of the machines.

An object of the present invention is to improve heat exchangers by providing means for an intermittent rapid shifting of the heat exchange matrix from one fluid conducting means to another. a

Another object of the invention is toreduce heat exchanger leakage by providing means intermittently actuating the heat exchanger and selectively indexing-heat exchange matrix passages with alternate fluid ducts.

A further object of the invention is to improve heat exchangers by providing a rotatable drum having a plurality of matrix passages, the drum being intermittently oscillated or rotated to index each passagefor a period of dwell with alternate fluid ducts.

Yet another object of the invention is to reduce heat exchanger leakage by providing an actuated pressure seal that cooperates with intermittent actuation of the heat exchanger to provide a tight seal during periods of dwell only.

For a more complete understanding of the invention, reference may be had to the accompanying drawings, illustrating a preferred embodiment of the invention in which like reference characters refer to like parts throughout the several views and in which- Fig. l is a diagrammatic view of a preferred movable heat exchange structure substantially as seen from the line 1-1 of Fig. 3 and illustrating a preferred hydraulic actuating means therefor.

Fig. 2 is a diagrammatic view similar to Fig. 1 but illustrating a modified actuatingmeansr.

Fig. 3 is a fragmentary longitudinal cross-sectional view of a preferred type of heat exchanger embodying the invention,

Fig. 4 is a fragmentary cross-sectional view of another type of heat exchange structure taken substantially on the line 4-4 of Fig. 5.

Fig. 5 is a fragmentary longitudinal cross-sectional view of the heat exchanger illustrated in Fig. 4, and

Fig. 6 is a fragmentary cross-section of the pressure seal embodied in the invention taken substantially on the line 6-6 of Fig. 2.

Referring to Figs. 1 through 3, a preferred heat exchanger 10 is illustrated as comprising fluid ducts 11 interrupted by an intermediate heat exchange structure 12 preferably constructed as a rotatable drum having a plurality of annularly arranged passages 12a filled with any desired type of heat exchange matrix or material 13.

2,965,361 Patented Dec. 20, 1960 In the usual embodiment of such a conventional drum type of heat exchanger, hot and cold fluids are conducted through respectively alternate ducts 11, which are annularly arranged to match the annular arrangement of thedrum passages 12a. Heat is thus absorbed by the matrix 13 of alternate passages 12a, the drum is rotated to align the heated matrix passages 12a with the cold fluid ducts 11 and to align the cold matrix passages 12a with the hot fluid ducts 11, such that as the matrix in alternate passages 12a give up the absorbed heat to the cold air flowing through alternate ducts 11, the matrix in the other passages 12a are being heated.

Heretofore, the rotation of the drum 12 was continuous, and of course during movement, closed segments had to be provided between alternate ducts to reduce pressure and fluid leakage between ducts. Even so, pressure and fluid leakage occurred, and the interval between exposure of matrix to alternate hot and cold fluids made for ineflicient heat exchange. It is seen in the present case that the ducts 11 and passages 12 are each immediately adjacent the next respective ducts and passages, and of course continuous rotation would necessarily make open connections between adjacent passages.

The present invention, however, contemplates intermittently moving or rotating the drum very rapidly to index the passages 12a alternately with the hot and cold fluid ducts 11, and providing a period of dwell between relatively short periods of movement, thus reducing leakage loss time to a minimum. Any desirable actuating means may be utilized for operating the drum in the above manner, and one method is illustrated in Fig. 1 as follows: An arm or lever 15 is splined or otherwise secured to a hub 16 secured to the drum 12 on its longitudinal axis. Suitable linkage 17 connects the lever 1.5 with a piston 18 operable in a hydraulic or pneumatic cylinder 19. The stroke of the pi ton is preferably limited by stops 20 so that at each end of the piston stroke the drum passages 12a are indexed with the ducts 11. A pilot valve 21 is provided with a pressure inlet port 22 in the center, a drain port 23 at each end, and intermediate ports 24 connected by conduits 25 with respective ends of the cylinder 19.

A valve piston 26 is reciprocated by rotation of a motor 27 or any means to direct pressure alternately to each end of the cylinder 19 and vent the other end to reciprocate the pi ton 18. It will be seen that the system provides a period of dwell between strokes of the piston 18 dependent on the speed of reciprocation of the piston 26.

Where it is desired that the drum 12 be rotated intermittently instead of oscillated, the lever 15 may be pivoted on the drum 12 as shown in Fig. 2 and provided with an actuating arm 30 which operates to turn a ratchet element 31, which is secured to the drum 12, in one direction only on every other stroke of the piston 18.

Instead of axial fluid flow through the: drum passages 12a, other arrangements may be made, one being illustrated in Figs. 4 and 5. Here, inner fluid ducts 35 and outer fluid ducts 36 are shown, being intercepted by an intermediate drum 37 having radial passages 38.

The arm 15 in this modification would be secured or pivoted, whichever type of actuation is desired, on a hub 39 secured to a plate 40 on which the drum 37 is mounted. Fluid flow is thus directed radially between the inner and outer ducts 35 and 36 respectively through the passages 38, each alternate duct 35 and each alternate duct 36 conducting hot and cold fluid and the passages 38 being selectively intermittently indexed alternately with ducts conducting hot and cold fluids.

In order to maintain maximum leakage sealing charthe foregoing heat exchanger structures, without restricting motion of the drums, some sort of actuated pressure seal should be provided between the edges of the ducts and passages.- A preferred arrangement of a seal 41 is shown in the detail of Fig. 6, in which a channel 41a issecured to the'edge of the duct 11 and supports an oppositely faced channel 42 to provide an adjustable enclosing space for a flexible tubing 43. The outer face of the channel 42 preferably rides on a plate 44 secured to the edge of the passage 12a.

The tubing 43 is adapted to be pressurized by any hydraulic or pneumatic means by pressure supplied through a conduit 45 intimed cooperation with actuation of the drum 12,50 that pressure will provide a tight-seal only during periods'of dwell and will be relieved when the drum 12 is being rotated or oscillated.

Such a means for sealing the oscillating drum is shown in Fig. 1, the conduit 45 being connected to intermediate ports 46 in the cylinder19. The piston, moving in the direction shown by the arrow 47 will open one of the ports 46 when it reaches the end of the stroke, thus directing pressure into the conduit 45. During the subsequent period of dwell, pressure sealing will be maintained. But when pressure is directed to the other end of the piston 18 and the former end is simultaneously connected'with drain, pressure in the tubing 43 is relieved, and: the piston 18-moves in the other direction, opening the other port 18 atthe 'end of the stroke to once more 7 direct pressure to the tubing 43 for effecting a tight pressure seal between the duct and passage edges. Forsealing the rotary drum 12'shown in Fig. 2, everythingis th'e same 'except that one of the ports 46 is lo cated to: be closed only at the-extreme end of one operat-: ing-*cycl'e thustmaintaining pressure during the "return stroke of the piston 18 when the drum is not being ro tated'as well: as when the 'piston l8 is'at rest during'periods of dwells: Pressure in the line 45 is'thus relieved only during the operative stroke of the piston as indicated by the arrow 47. In summary, it is noted that in all embodiments of the invention, whether as shown or otherwise, the motion of the structure effecting alternate flow of fluids through the heat exchange material or matrix is intermittent rather than continuous. Motion may be either in one direction or back-and=forth and the time of motionis small compared with the time of dwell; that is, movement is so rapid-that the-time for leakage is very small." Also, tight pressure seals may-be provided to eliminate leakage during the dwell period, the pressure being-relieved only to permit the required'actuation. It will be also be observed that the use of a plurality of 'smallpassages and ducts permits the time of motion between dwell periods to be reduced, thus furtherv eliminating leakage.

'Iclaim:

1. In a heat exchanger comprising two fluid conducting means and a'heat exchange structure for transferring heat from fluid flowing in one conducting means to fluid nular rims, said conducting means comprising conduits 4 flowing in the other conducting means, said heat exchange structure comprising a single" annular drum rotatable on its longitudinal axis and having a plurality of equally annularly spaced longitudinal partitions defining segment passages provided with heat exchange material, actuating means intermittently rotating said drum on its axis through an arc relative to the spacing between adjacent partitions and selectively indexing said passages alternately in open-communkationwith said conducting means, the ends of said-drum having inner and'outer annular rims, said conducting meanscomprising conduits having annular rims registering at all times with the rims of said drum, leakage sealing means comprising annular expansible tubular elements disposed intermediate the registered rims'of said drumand said conduits, control means intermittently contracting and expanding said tubular elements in timed cooperation with said actuating means and operable when expanded to provide a positiveseal against fluid-leakage only when said drum is at rest."

2. In a heat exchanger comprising two fluid conducting means and a-he'at exchange structure for transferring heat from fiui'd fiowing in" the conducting means to fluid fiowing'in the other conducting means, said heat exchange structure-comprising a single annular drum ro tata'ble' on its longitudinal axis and having a plurality of equally annularlyspaced longitudinal partitions defining segment passages provided with heat exchange material, actuating means intermittently rotating said drum on its axis through an are relative to the spacing between adjacent partitions an'dselectively indexing said passages alternately in open" communication with said conducting m'eansg tlie-ends-of said drum having inner and outer an sealagainst fluid leakage only when said drum is at rest,

said control means comprising a fluid pressure-means operably connected with said actuating means and operable to directfluid' pressure to said tubular elements to expand same only" when said rotating said-drum:

References Cited in the file of this patent UNITED STATES PATENTS 870,546 Cooke Nov. 12, 1907 1,558.445 Ljungstrom' Oct. 20, 1925 2,700,537 Pennington Jan. 25, 1955 28633644 Fallon Dec. 9, 19 58 FOREIGNPATENTS 459,992 Canada Sept. 27, 1949 actuating means is not 

